


Kryptonite

by DarkColdSummer



Category: Undertale (Video Game)
Genre: Alphys as Volt, Alternate Universe - High School, Alternate Universe - Human, Alternate Universe - Superheroes/Superpowers, Asriel as Flowey, Blooky as Ghost, Chara & Frisk (Undertale) are Siblings, Chara as Fallen, Fantasy, Frisk as Blood, Gaster as Void, Gen, Kidnapping, MK as Stripe, Mettaton as Bot, Nonbinary Chara & Frisk (Undertale), Nonbinary Chara (Undertale), Nonbinary Frisk (Undertale), Nonbinary MK, Nonbinary Monster Kid, Nonbinary Napstablook, Orphan Asriel, Orphan Chara, Orphan Frisk (Undertale), Orphan MK, Papyrus as Font, Sans as Comic, Selectively Mute Frisk (Undertale), Stealing, Superheroes, Supervillains, Teenage Chara (Undertale), Teenage Frisk (Undertale), Undyne as Life, nonbinary characters - Freeform
Language: English
Status: Completed
Published: 2018-09-14
Updated: 2018-09-14
Packaged: 2019-07-12 03:03:43
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,628
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15986258
Author URL: https://archiveofourown.org/users/DarkColdSummer/pseuds/DarkColdSummer
Summary: Ebott's Wake really couldn't stand whenever a random tip ended up revealing The Outcasts. The Outcasts, similarly, didn't enjoy being interrupted by them. Sans enters a new school, only to be taken in by a group of mismatched friends - Chara, Frisk, Asriel, MK and Blooky. (Of course, you can guess what happens.)





	Kryptonite

"Careful Stripe!" Flowey hissed. "And hurry! The others are already ahead of us!"

 

Stripe nodded carefully, manoeuvring through the laser alarms with a practiced ease. After hopping over the last one, they followed Flowey and caught up with the others.

 

"What are we looking for again?" Ghost whispered.

 

Wordlessly, Blood pulled up a hologram image from the machine on their arm. The image of a beautiful amethyst cast in a ring of gold, looking ancient yet ever so modern, stared right back at the group.

 

"Right," Ghost nodded as the hologram image deactivated.

 

"Pshhh..." Fallen huffed. "Idiots."

 

Flowey glared at Fallen, who only stuck their tongue out at him in return.

 

"Stop!" A commanding yet soft feminine voice echoed through the museum.

 

"Dammit," Fallen cursed, echoing the sentiments of the entire group.

 

"We got a tip that..." Life started, before her eyes rested on The Outcasts. "Oh. You again."

 

"Get the thing," Flowey hissed to Blood and Ghost, and the former nodded while scampering off into the darkness and the latter phased through the walls.

 

Flowey pulled up a rainbow coloured sword, little white "Friendliness Pellets" and stars surrounding him. Stripe's signature orange and green whips were at the ready. They lashed them threateningly, grinning as Bot flinched while the whips changed to purple. Fallen summoned two red knives to grasp in their hands, ready to strike at command.

 

"Who's there?" Volt's cracky voice echoed through the comms.

 

"The Outcasts," Life murmured back.

 

She then sighed and formed a light blue spear in her hands. Bolt shrugged but formed little bolts of yellow. Comic pulled up a giant blaster (or two) and Font initiated the fight with waves of waves and bones.

 

All hell broke loose.

 

.

 

Ghost hummed to themselves as they weaved their way through the walls, phasing in and out into the empty corridor, watching as various lights flashed in the dark hallways behind them. When they phased out, Blood tapped their shoulder, pointing to their target. Ghost nodded and half-phased, pulling the ring out of its casing.

 

The duo headed back towards the flashing lights.

 

.

 

"Get a taste of HD!" Flowey yelled, sword sending rainbow streaks towards the members of Ebott's Wake.

 

Life grunted and activated the shield that Volt made for all the members. Her unique green shield spread open and just barely absorbed the rainbow attack, then bouncing it back. Flowey couldn't dodge it fast enough. He closed his eyes, and braced himself to take his own attack...

 

...But it never came.

 

He opened his eyes to see Blood in front of him, their distinct red Determination shield defending the both of them from the attack.

 

"Thanks," he breathed, and Blood nodded silently, sending a pulse of DT magic out to the rest of The Outcasts, healing any minor scrapes they had. "Do you have the thing?"

 

Blood nodded.

 

"Good," Flowey grinned. "Let's go."

 

Fallen, who had heard what Flowey said, grinned menacingly. They gathered DT... and unleashed it in a sonic boom.

 

By the time the red smoke cleared, The Outcasts were nowhere to be found.

 

"Damnit," Life swore.

 

"Again?" Font sighed.

 

"Let's just go," Bot suggested. "We can catch them another time."

 

Comic grinned and collapsed on the ground. "Welp bro, guess you gotta carry me back. I'm bone tired."

 

Font groaned, rolling his eyes, but picked the smaller brother up anyway. "Let's go."

 

Up above, in the vents, The Outcasts chuckled at the scene and exchanged hi-fives.

 

Mission accomplished.

 

.

 

"SANS!" Papyrus called. "Come down! Its time for breakfast!"

 

"Five more hours," Sans replied, his voice muffled through the pillow.

 

"SANS! YOU'RE GOING TO BE LATE FOR SCHOOL!"

 

"Whatever."

 

"SANS!"

 

.

 

"Stupid children, stupid things, stupid, stupid," Undyne groaned, smashing her head against her lap with every "stupid" uttered.

 

"There, there," Alphys, her girlfriend, sighed, petting her back. "You knew what you signed up for when you decided to be a gym teacher."

 

"But not... this!" Undyne exclaimed, waving her hands at the scene in front of the duo.

 

Kids were running about, wracking havoc in the gymnasium. Dodgeballs and basketballs were being thrown all over the place, and Alphys ducked, a tennis racket (what?!) just barely missing her head.

 

"Never mind. It is possible that you may have a problem."

 

.

 

"Hiya!" Asriel grinned, throwing the dodgeball with all his might. "Ha! Take that Frisk!"

 

Frisk grinned, swiftly dodging the dodgeball with a dancer's grace, and secretly gestured for MK to retaliate. MK grinned, and launched multiple dodgeballs in succession at Asriel and Chara. Too late, they didn't dodge, and were both out of the game. Frisk and MK exchanged hi-fives.

 

"'s not fair Frisk!" Chara groaned. "You're too good at this game!"

 

Frisk simply stuck out their tongue at their sibling.

 

"You're terrible!" Chara pouted.

 

Frisk still smiled sheepishly, before catching the eye of a boy in a blue hoodie. They grabbed Chara's wrist and despite the latter's protests, dragged them over to the newcomer.

 

Frisk started signing eagerly, and Chara rolled their eyes. "Stop it Frisk, let me."

 

.

 

Sans was completely and utterly shocked when the two other kids came up to him. Here he was trying to avoid attention... Guess he'd have to fix that.

 

"Greetings. I'm Chara, and this is my sibling Frisk. They/them pronouns for the both of us please. Frisk wanted to know if you're new here and if you wanted to join us and our friends in playing dodgeball or something," the one with red eyes, or Chara, asked.

 

"Sure," Sans shrugged, in a noncommittal gesture. "The name's Sans, by the way."

 

"Great!" Another voice piped up from behind the duo, shocking Sans just a little. "Yo! I'm MK!"

 

"And I'm Asriel," Asriel grinned.

 

Frisk started using heir hands to sign rapidly again, leaving Sans looking blankly at the flurry of signs.

 

"Oh right!" MK (what kind of name was that?) grinned. "Let's call Blooky!"

 

"You called?" A pale figure asked, a small smile on their face.

 

"Blooky!" Asriel grinned. "Blooky, Sans, Sans, Blooky. Now let's go! Me, Chara and Blooky versus the rest of you!"

 

.

 

"You cheated," Chara pouted, glaring at the opposing team. Frisk and MK chuckled and exchanged hi-fives. Then Frisk spun around and offered a hand to Sans.

 

Sans looked skeptically at the hand then hi-fived Frisk.

 

"PFFFFFTTTTTTTTTtttttttttttt...."

 

Silence within the group amidst the laughter of other students and screaming of their teacher Ms Undyne.

 

"The old whoopie cushion in the hand trick," Sans laughed to himself. "Always gets them."

 

Much to his surprise, the rest of the group started laughing, Chara especially.

 

"Finally! Someone with a decent sense of humour!" They laughed. "We're kidnapping you and taking you with us. No returns."

 

Sans found himself being dragged away by the red eyed teen.

 

"Sorry," Frisk whispered to him. "Azzy gave Chara chocolate to wake them up. They're too high to fully comprehend anything."

 

.

 

"Damn those kids," Life swore a few days later, taking off her mask back at their base. "Stupid, stupid kids. They're almost as bad as the kids I teach!"

 

"'ya mean try to, Undie," Comic laughed. "Heck, I'm in one of your classes and I don't think you've taught anything substantial yet."

 

"Sans! Don't be mean!" Font-Papyrus scolded, taking off his brother's mask for him.

 

"Hey, it's the truth!"

 

"Speaking of school," Undyne countered, a glint in her eyes. "How about those kids that you're hanging out with a lot now?"

 

"Really? My brother has new friends! Wowie!" Papyrus grinned, grabbing Sans and spinning him around.

 

"Careful there!" Alphys-Volt stuttered, backing away from the pair of brothers.

 

"It's fine, Alphie. A little brotherly bonding doesn't hurt," Bot countered, leading Alphys a little further away.

 

"...You're right, Mettaton."

 

"The red eyed kid - Chara - was high on chocolate that first day! That doesn't count!"

 

.

 

"HA!" Stripe yelled, attempting to kick Ghost but failing since the latter turned themselves intangible just before they hit. "Aww..."

 

.

 

"Um, hey," Sans started, approaching the group. "My brother wants to meet you guys. Are you okay for after school?"

 

The group exchanged looks.

 

Frisk clenched their hand into a fist, and moved it down in a sign Sans had learnt to recognise as "can".

 

"Eh," Chara shrugged. "Why the hell not?"

 

Asriel shot Chara a look that almost clearly said, "Why the hell would we?"

 

.

 

"Welcome, Sans' friends!" A loud and boisterous voice called out. Bright eyes met the group of teenagers at the door. "I am the great Papyrus, Sans' brother!"

 

"Greetings," Chara grinned. "I am Chara. The demon that comes when you call its name. It doesn't matter when. It doesn't matter where. Time after time, I will appear. And with your help, we will eradicate the enemy and become strong."

 

Papyrus stared blankly at Chara, then went back to his previous mood. "Well then, Chara the demon and Sans' friends, welcome to my humble abode!"

 

Chara stared as the older male bounced back into the house. "He doesn't get it, does he?"

 

They walked in as a group.

 

"Ms Undyne?!" Asriel gasped, jumping backwards, then spotted a familiar figure wearing a blue jacket. "Sans! Why are you friends with our teacher?"

 

"She's Pap's friend," Sans shrugged in a non-committed manner. "Didn't expect her to have the patience to put up with teens our age as a teacher though."

 

.

 

"I'm adopting this one."

 

"Undyne..."

 

"I said, I'm adopting this one! Which part of that is so difficult to understand?"

 

"You're 7 years apart."

 

"So?"

 

Frisk giggled from within Undyne's iron grasp while Papyrus sighed in exaggerated exasperation. Undyne simply pouted.

 

.

 

"Boom! Boom!" Stripe laughed whiled lashing their whips at the poor mutilated training dummy. "Do you know? Life is so cool!"

 

"Life as in living-life or life as in Wake-Life?" Fallen asked, puzzled.

 

"Undyne-Life!"

 

Everyone looked at Stripe.

 

"What?!" Stripe asked. "I sneaked a peek in her bag. Life's suit was there. Undyne is Life!"

 

"That just means we have to be more careful around her," Flowey said sternly.

 

If possible, Blood pouted even more than Stripe. For no reason in particular, of course. No reason at all.

 

.

 

In a secret lab, deep at night, Void laughed and laughed and laughed. His maniacal laughter would have chilled anyone who heard it to the bones.

 

Still laughing, he created an inter-dimensional portal and yanked two people out of their respective beds.

 

Time to have a little fun.

 

.

 

"So... I guess we're kinda stuck together now," Sans said blandly.

 

Frisk fixed him with a blank stare. "No, genius," they croaked out, amusement laced in their tone.

 

Sans sent a wry grin back before the door to the blank room they were locked and bound in was opened.

 

“Hello, my son!” Void grinned.

 

“Hello, _Gaster_ ,” Sans snarled, his easygoing grin completely gone, in its place a feral frown.

 

Frisk blinked, then tucked themselves tighter into their corner. Whatever was going down, they didn’t want any part in it.

 

Sans growled, and his eye lit blue (though Frisk didn’t notice it), before he remembered Frisk’s presence and extinguished the blue flame growing in his eye.

 

Gaster grinned.

 

Way too much fun.

 

.

 

“Where the heck is Frisk?” Chara yelled when they woke up in the orphanage that day and Frisk was nowhere to be found.

 

Asriel, in the bed next to them, shook himself up, bleary eyed, and glanced over at Frisk’s bed, only to not find anyone.

 

MK, who had also been woken up by Chara’s yelling, groaned. “Shut up Chara. They probably woke up early for breakfast or something.”

 

Blooky strolled into the room. “Hey, I heard yelling from downstairs. Anything happening?”

 

Chara took the opportunity and grabbed Blooky by the arm. “Have you seen Frisk?”

 

“No… why?”

 

“FRISK IS GONE!”

 

“SHUT UP CHARA!” Someone from the room next door yelled.

 

“SCREW YOU!”

 

.

 

“Undyne,” Papyrus asked over the phone while making breakfast. “Could you check if Sans goes to school today? I woke up this morning and he wasn’t in his room.”

 

“Of course, Papyrus!” Undyne replied cheerfully, a grin on her face.

 

.

 

“NGAHHHHHHHHHH!” Undyne screamed into the phone. “I CAN’T FIND YOUR LAZYBONES BROTHER ANYWHERE!”

 

.

 

Two Outcast-typical pieces of graffiti lay outside Frisk’s orphanage and Sans’s home.

 

“Come get them if you want.”

 

.

 

Undyne growled.

 

.

 

Chara smirked.

 

.

 

Challenge accepted.

 

.

 

Fallen stood at the front of their group, staring down Void with their red eyes. "We are The Outcasts, demons that come when you call our names. It doesn't matter when, it doesn't matter where. Time after time, we will appear. And we would help you eradicate the enemy and become stronger, but you have our friends there."

 

Frisk grinned at their sibling and the rest of the team. Sans was just looking on, blank-eyed. "Cha-ra...?"

 

"NGAHHHHHHHHHH!" Another voice joined the fray, Life landing a similar distance away from the supervillan, the rest of Ebott's Wake landing themselves behind her. "YOU HAVE SOME PEOPLE WE WANT BACK!"

 

Frisk's eyes darted across the group members of Ebott's Wake, before returning their gaze to Sans. "Seriously? All code names in the world. Comic."

 

Sans smiled sheepishly. "Like you're one to talk... Oh right. Blood."

 

"What are they doing here?" Font asked loudly, pointing at The Outcasts.

 

Asriel grabbed on to Fallen's arm, ensuring the latter didn't just run off to slap Font or something like that. "Hey, we know who they are, but they don't know who we are. Calm down."

 

"MS LIFE YOU'RE MY IDOL!" Stripe screamed.

 

Fallen, Flowey and Ghost stared at Stripe, as did the members of Ebott’s Wake.

 

"What?!" Stripe asked. "Its true!"

 

"Look, Frisk is our last member like Sans is yours, we want them back as much as you want Sans," Fallen warned Life threateningly, right in front of her. Flowey blinked. He didn't even notice Fallen leave his grip. "Just work together and deal with it. We can figure out who we actually are later."

 

Life nodded. "Yes, hostage situation - freeing the hostages is most vital."

 

"Good that we're on the same page," Fallen grinned, teeth bared in a feral manner. They snapped around, weapons at the ready. "Determination, go!"

 

"Get a taste of.... HYPERDEATH!"

 

"ATTACK!!"

 

Floods of weapons appeared, rushing towards the supervillan. Void grinned, and disappeared, leaving the attacks to head towards the two hostages. Frisk's eyes glowed red momentarily, and a DT shield formed in front of the both of them.

 

"Thanks a ton, Blood," Sans grinned, then teleported out of his bindings. "C'mon."

 

Frisk glared at Sans, but a red knife sliced clean through the bindings before they could complain. They smiled at Chara in thanks. Chara did an absent-minded two-fingered salute in response, summoning new DT knives and launching them toward Void again.

 

.

 

***two hours later**

 

“Fuck this,” Chara swore, forming a new DT knife in their hand to strike at Void once more. “Screw this.”

 

“Heh,” Sans laughed shortly to himself.

 

“Shut up, comedian,” Chara snapped.

 

“Heh.”

 

“Hey Chara,” Asriel cut in before Chara could go all murder-y on Sans. “How about we do our special combined attack?”

 

Undyne gasped silently to herself. No way Fallen was Chara. But… seeing how Frisk was Blood…

 

Chara grinned widely. “Fabulous idea there Azzy! Hey Frisky! Come join us!”

 

That would make Flowey Asriel… And Stripe acted a lot like MK… Did that make Ghost Mettaton’s distant cousin - Blooky?

 

Unknowing of Undyne’s dilemma, Asriel pulled out a small rainbow HD star, letting Frisk infuse DT into it. Chara formed little red DT knives as wings for the little star. Together, they shrunk it even more, then let Asriel let it lose. It hovered there, waiting for activation, out of sight. Frisk sent out a quick modification, making it blow when near only Void, also restricting usage of magic during the attack period.

 

.

 

***another half an hour later**

 

_BOOM._

 

Ecstatic, Asriel, Chara and Frisk exchanged eager hi-fives.

**Author's Note:**

> The Outcasts - minor "villains" - they do advocacy vandalism and sometimes heists for things that were stolen in the first place  
> Frisk (15) - Blood - Uses DT to heal others, can also use DT shields  
> Chara (15) - Fallen - Makes little sharp red knives out of DETERMINATION - DT weapons have Karmic Retribution on them  
> Asriel (16) - Flowey - "Friendliness Pellets", uses most forms of magic (Love, Bravery, Justice, Kindness, Patience, Integrity, Perseverance) - calls that Hyperdeath/HD   
> Napstablook (17) - Ghost - Can teleport and phase through walls, Justice magic tears  
> MK (15)- Stripe - Makes whips with Bravery, Kindness and Perseverance magic
> 
> Ebott's Wake - Superheroes  
> Sans (16) - Comic - Bones and GBs with Justice, Patience and Integrity magic, can teleport  
> Papyrus (18) - Font - Bones and Waves with Bravery, Patience and Integrity magic  
> Undyne (22) - Life - Spears with Patience and Kindness magic, super stamina  
> Alphys (21) - Volt - Communications Manager, equipment designer, doesn't go on field normally, has a bunch of mini-robots to attack using Justice  
> Mettaton (21) - Bot - Bolts with Patience and Justice magic, super strength
> 
> Crazy extreme supervillain  
> Gaster - Void - Can summon black holes and a whole bunch of other evil things - kidnaps Sans and Frisk
> 
> ...
> 
> ...
> 
> I couldn't think of a good ending point for this sorry.


End file.
